This invention generally relates to injectors and fuel nozzles for high temperature applications, and more particularly, to fuel injectors and nozzles for gas turbine engines.
Gas turbine engines used in military and commercial aircrafts must satisfy high demands with respect to reliability, weight, performance, economic efficiency, and durability. Turbine engines typically include a plurality of fuel injectors configured to inject fuel in a spray or atomized form into a combustion chamber of the engine. The atomized air/fuel mixture is then combusted to create the energy required to sustain engine operations.
The atomization of the fuel/air mixture is generally achieved by mixing the fuel with a turbulent, non-linear air flow. To create a turbulent air flow in conventional fuel nozzles, an air swirler is positioned at an upstream end of the nozzle within the interior air flow path. As the air flows over the air swirler, the air is forced to swirl about the circumference of the passage. Because the air swirler is arranged at the upstream end of the nozzle, the swirl generated dissipates as the air travels over the length of the nozzle. By the time the air flow reaches the downstream end where it is mixed with the fuel, the swirling of the air flow may be diminished, thereby reducing the atomization of the mixture.
Conventional methods for manufacturing components of a gas turbine engine include machining, forging, and investment casting. Material selection for the components that are subjected to high mechanical loads, high vibration loads, or high thermal loads is often based upon material limits being exceeded in localized regions of the component. Because high-strength materials are needed, the cost of the component is largely driven by the amount of material used, so elimination of excess weight can significantly reduce part or component cost.